6.4 Transport and Assimilation of Absorbed Nutrients

Question 1

what is assimilation

Answer 1

Assimilation is the process whereby some of the absorbed food substances are converted
into new protoplasm or used to provide energy.

Question 2

state the function of the hepatic portal vein as the transport of blood rich in absorbed nutrients
from the small intestine to the liver

Answer 2

• Blood capillaries from the small intestine join together to form the hepatic portal vein, which
  transports nutrients to the liver.
• Glucose is assimilated and then oxidised during tissue respiration to release energy for the
  vital activities of the cells.
• Excess glucose is returned to the lover and stored as glycogen. Insulin stimulates the liver
  cells to convert excess glucose into glycogen. Glucagon stimulates the liver to convert
  glycogen back into glucose.
• Amino acids which enter the cells are converted into new protoplasm that is used for growth
  and repair of worn-out parts of the body.
• Amino acids are used to form enzymes and hormones.
• Excess amino acids are deaminated in the liver.

Question 3

Assimilation Fats

Answer 3

• Fats are absorbed into the lymphatic capillaries. The lymphatic capillaries join to form larger
  lymphatic vessels, which discharge fats into the bloodstream.
• Under normal conditions when there is a sufficient supply of glucose, fats are not broken
  down, but are used to build protoplasm.
• When glucose is in short supply, fats are broken down to provide energy needed by the
  body.
• Excess fats are stored in the adipose tissues beneath the skin and around the heart and
  kidneys. They act as shock absorbers.